Abstract: A device for measuring a physical quantity, including at least a transceiver unit for electromagnetic waves, an antenna-sensor including a sensor integrated into a target antenna having at least one excitation port, the antenna-sensor having a variable impedance with electromagnetic transduction, the measuring device being configured, per predetermined frequency band and independently of the angular difference between the transmission and reception of waves, for measuring the electromagnetic response of the antenna-sensor at least from an ellipticity rate of an electromagnetic field backscattered by the antenna-sensor, the ellipticity rate characterizing the polarization of the electromagnetic field configured to be measured by the transceiver unit, the electromagnetic response being representative, by electromagnetic transduction, of the at least one physical quantity to be measured.